WISP searches by Tokyo tabletop experiments group UTokyo tabletop experiments group Toshio NAMBA 0
UT tabletop experiments group (only related to today’s talk) •UTokyo Physics & ICEPP : S. Asai, T. Inada, T. Yamaji, T. Yamazaki(KEK), ... + S. Knirck(Heidelberg) Core members •RIKEN, JASRI (SPring-8&SACLA): K. Tamasaku, Y. Inubushi, M. Yabashi, T. Ishikawa, ... X-ray experts •UT ISSP & Tohoku Univ.: A. Matsuo, K. Kindo, H. Nojiri Pulsed magnet experts •Fukui Univ. FIR: T. Idehara, .. Millimeter wave experts 1
WISPs (Weakly Interacting Slim Particles) •Many extensions of the Standard Model predicts particles in hidden sectors which are only weakly coupled to our visible sector. •Usually, relatively light (<~eV) hidden sector particles are called as ‘WISP’. •A lot of new exotic these particles can arise, but, in this talk, two kinds of WISPs are discussed. • Hidden photons (or paraphotons) • Axion like Particles (ALPs) 2
Hidden photons Hidden photon Photon γ ! γ f Heavy fermions with both U(1) charges • Extra gauge bosons of hypothetical U(1) symmetry • Tiny kinetic mixing c with ordinary photons ℒ int = − ' *+ , *+ 2 ) • Neutrino like flavor oscillation • Tiny fraction of mixing can be separated by an ordinary mirror • Can be cold dark matter (CDM), if their parameters are reasonable 3
Axion Like Particles (ALPs) g ����� ALPs ������� ������������� ����������� � g ������� ������������ � • Originally motivated by the strong CP problem • CPV caused by q vacuum can be cancelled by SSB of PQ symmetry → New NG boson, axion • More generally, axion like particles are predicted by string theory or SUSY/SUGRA (No constraints on mass-coupling relations) • ALPs interact with two photons (Primakoff process) % &'' *+ , ) *+ - = / "## 0 1 2- ℒ "## = − ) ( or are converted to photons under EM field • Also are good candidate of CDM 4
Many searches for WISPs • Many searches are based on the WISP-photon conversions • From the experimental view, the difference between hidden photon and ALP is the conversion method Hidden photons: Appears through its kinetic mixing ALPs: Additional magnetic field (EM field) is required • Assumed sources of WISPs should be cared when their comparison Very ambitions? one: Whole CDM component is WISPs (ADMX, etc.) Stars are well-known: Emitted from astrophysical objects (CAST, etc.) Most rigid one: WISPs are artificially created (ALPS, etc.) 5
Our WISP searches with various methods 1. Hidden photon dark matter search in DM search millimeter-wave region 2. Hidden photon search 3. ALP search by pulsed magnets Laboratory search @X-ray facility 4. ALP search by crystalline electric fields 6
(ordinary EM wave) Converted light HP Strength Hidden photon dark matter search in milli- wave region • Hidden photon source: Cold dark matter Done by S. Knirck from Heidelberg During his half year stay in Japan - '( 0~10 ,2 ! "# = %& '( ⃗ * conductor + , - ' ~ 0 • Select tiny fraction of photon components by using a conductive plate. • Energy of converted light = Mass of HP 7
Target region: Millimeter wave region • m HP ~meV region corresponds to millimeter wave = A marginal region between photon and radio wave (a little bit difficult to handle) • Constraint is not so stringent around this region LSW Coulomb Solar lifetime Solar HP CMB distortions Millimeter wave Dish (optical) Collaborate with millimeter HB wave experts in Fukui University ADMX 8
Conversion Plate 600*600mm，Al Schottky barrier diode mixer(SBD) 155~220GHz Corrugated Horn (connected to SBD) Parabolic mirror HP Parabolic mirror f=1500mm，Al Setup of the HPDM search ! " # = 0.6~0.9 !*+ Φ500mm(area : 0.2! . )， 9
Al conversion plate Parabolic mirror 1500mm SBD LO oscilloscope SBD (large view) horn These setups are placed in a radio dark room in Fukui University. Data taken from Nov. 2016 to Mar. 2017 10
Obtained result • If HPDM existed, a peak would appear at its mass. • From the absence of such a peak, kinetic mixing ! ≿ 10 %& is excluded for 0.67<m HP <0.92meV (90%C.L.). • JCAP 11(2018)031. − 5 10 Coulomb χ 6 − 10 Kinetic mixing LSW FIRAS H e l i o − 7 s 10 c o p e s Helioscope (Xe) ( v a c u u m Now working for ) 8 − MADMAX project 10 9 − 10 1 − 10 1 10 11 HP mass (meV)
Hidden photon search at X-ray facility • (Maybe just my biased opinion), we, particle physicists want to search new particles without cosmological/astrophysical assumptions. Dr. T. Inada M thesis • Create WISPs by ourselves & detect them by using strong light sources. • Our source: SPring-8 synchrotron facility • BL19LXU: One of the most brightest hard X-ray source • 10 13 ~10 14 X-rays/s for 7.2~30keV SPring-8 Undulator @BL19LXU 12
Light Shining through a Wall (LSW) method • Convert photons to WISPs ⇒ Shield photons at a wall ⇒ Re- convert WISPs to photons ⇒ Detect photons Wall to shield photons Photon Photon WISP Light source Detector Photon-WISP conversion 13
Light Shining through a Wall (LSW) method • Convert photons to WISPs ⇒ Shield photons at a wall ⇒ Re- convert WISPs to photons ⇒ Detect photons • For hidden photon ⟺ photon conversion # & 2 γ = 4 χ 2 sin 2 m " γ P L % ( % ( γ → " 4 ω $ ' Oscillation in vacuum Wall to shield photons Photon Photon Hidden photon Light source Detector Photon-Hidden photon conversion 14
Search setup in the beamline ��������� � ������������ � ���������� � Wall ����������� ���������� ��������������� ������ � ��������� � ������ � ������������� � ������������� � ������������ ����������� � ������� � �� � �� � ������ � ������� � ���� � ��������� � Conversion Re-conversion Ge detector (Canberra BE2825) • Permanent apparatuses in the beamline were used for the LSW setup Pb shield • The search was performed on June in 2012 for 2 days. X-ray beam • X-ray energies were changed 9 times from 7.27 keV to 26 keV. • A germanium detector was used to detect re- converted X-rays. 15
Search Results -3 × 10 1 Example of the measured spectrum (9keV) 9.00 keV measurement counts / sec / 0.125 keV 0.5 0 -0.5 signal region data 95% C.L. upper limit -1 7 7.5 8 8.5 9 9.5 10 10.5 11 energy (keV) • No significant signals were observed in all data. • The spectra for other energies had also no peaks. 16
Search Results • No significant signals were observed in all data. • Constraints of ! < 8.06×10 )* for (0.04 eV < m HP < 26 keV) were obtained (95% C.L.) • Phys. Lett. B722(2013)301. The most sensitive laboratory search at 0.1~100eV region 17
Next: ALP search • We want to do ALP search similar as hidden photon search, but, dedicated magnets are required for the conversion. 2 2 l ! $ P = g αγγ BL , θ = m α sin θ # & 2 4 ω θ " % • Since the magnetic field should be applied perpendicular to the light path, and the conversion depends on (BL) 2 , usual solenoid magnets are not suitable. Wall Photon Photon N N ALP Light source Detector S S Dr. T. Inada designed and constructed coils & power supplies dedicated for the ALP search 18
Our magnet for ALP search Coil B field ������������� 20cm ������������� � X-ray path • Racetrack shape coils made of copper wire • Its length is L=20cm • Capsulated in a stainless frame to endure the magnetic field stress • Designed to be operated at pulse mode, 14.1T max, ~1ms duration (Good for S/N separation) • Cooled by Liq. Nitrogen 19
Power supply for the pulsed magnet Typical excited B field B [T] 14 Charging unit 12 10 14.1T 2m 8 � 6 4 � � 2 1.7m ~1ms 0 � Capacitors 0 0.5 1 1.5 2 2.5 3 time [ms] • Total 3mF capacitance (0.25mFx12capacitors) is charged to 4.5kV (30kJ power). • The rapid charging system enables 0.5Hz repetition rate. • Total 2ton weight (can be carried by motortrucks). • NIM A 833(2016)122 20
ALP search in BL19LXU Conversion coils Re-conversion coils • Performed in Nov. 2015 • 4 coils were placed at the X-ray path in the experimental hatch • 2 for (X-ray → ALP) conversion • 2 for( ALP → X-ray) re-conversion • X-ray energy was set to 9.5 keV # → ! ! → # • Net 2 days operation (total 28,000 excitations) Lead shield 21
Event distribution -3 10 × 0.8 Count / s / 0.4 keV Black: All events Red: Events when magnet excited x 100 0.6 0.4 � 100 ������� � �������������� 0.2 ����� � 0 0 2 4 6 8 10 12 14 16 Energy [keV] • No significant events correlated to the magnet excitations were observed. • BG rate is consistent with the one observed event. 22
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